542 



VITAL ACTIONS OF THE LOWER FUNGI. 



Intra-molecu- 

 lar respira- 

 tion. 



Decomposi- 

 tion when 

 oxygen is 

 admitted. 



ferment, gradually split up large quantities of suitable 

 complex compounds. We do not yet know accurately 

 the nature of the chemical bodies directly concerned in 

 this action of the protoplasm, nor in what way decom- 

 position takes place ; it is probable that the compounds 

 are nearly allied to the proteid materials, but are more 

 complex. As products of decomposition we constantly 

 observe carbonic acid, and also some other materials 

 which will be mentioned below. We may, however, 

 conclude from the amount of heat which becomes free 

 at the same time, although it is trivial, that the trans- 

 formation chiefly takes place in such a way that a more 

 complete union of the atoms and greater saturation of 

 the affinities, with consequent liberation of energy, 

 results. 



This whole process, which is evidently the primary 

 and true cause of life, is usually spoken of as "intra- 

 molecular respiration." For this process the access of 

 oxygen is unnecessary, on the contrary it is characteristic 

 of it that all vegetable cells can continue to live and 

 breathe for a time without oxygen, and split up carbonic 

 acid and produce heat. If substances capable of under- 

 going decomposition are still present in the living 

 protoplasm, their decomposition is sufficient to furnish 

 the necessary energy for the other processes which 

 take place in the protoplasm, and it is only after a 

 considerable time that there is such a deficiency of 

 energy as to lead to the cessation of movement and 

 life. 



Although, therefore, the intra-molecular respiration 

 is the chief and primary cause of development of energy 

 in the plant, the energy so obtained does not suffice 

 permanently to supply the whole amount required. 

 This is usually only obtained when oxygen has free 

 access, and when it takes part in the respiratory process. 

 The compounds broken up in the protoplasm furnish, 

 in addition to carbonic acid, a series of other products 

 which readily enter into combination with oxygen. Thus 

 extensive oxidations occur, and accordingly a more 

 marked development of vital energy which completely 



